Inhibition of corneal inflammation by the TLR4 antagonist Eritoran tetrasodium (E5564).
OBJECTIVE
To investigate the role of the TLR4/MD-2 antagonist eritoran tetrasodium in a murine model of contact lens-associated corneal infiltrates.


METHODS
C57BL/6 mouse corneas were abraded and treated with eritoran tetrasodium or placebo, either before or after stimulation with either LPS, the TLR2 ligand Pam(3)Cys, or antibiotic-killed Pseudomonas aeruginosa. A 2-mm punch from a silicon hydrogel contact lens was used to cover the corneal surface throughout the inhibition and stimulation period. Corneal infiltrates were detected by in vivo confocal microscopy and by immunohistochemistry for neutrophils. The effect of eritoran tetrasodium on stimulated human corneal epithelial cells (HCECs), macrophages, and neutrophils was also assessed.


RESULTS
Eritoran tetrasodium significantly inhibited CXC chemokine production in the cornea and development of corneal infiltrates, specifically neutrophils, in response to stimulation with LPS (TLR4), but not Pam(3)Cys (TLR2). When the antagonist was applied after LPS stimulation, neutrophil infiltration was also inhibited, although a higher concentration was needed. Furthermore, IL-8 production by TLR4- but not TLR2-stimulated HCECs, macrophages and neutrophils was also significantly reduced. Corneal inflammation induced by P. aeruginosa in the presence of tobramycin was found to be dependent on expression of TLR4 and MD-2 and is inhibited by eritoran tetrasodium.


CONCLUSIONS
Eritoran tetrasodium is a highly effective antagonist of TLR4/MD-2-dependent corneal inflammation.
Sun
Yan
Y
Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44106, USA.
Pearlman
Eric
E
D000818:Animals; D017209:Apoptosis; D054360:Chemokine CXCL1 / Q000378:metabolism; D003545:Cysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D004187:Disaccharides / Q000627:therapeutic use*; D019573:Epithelium, Corneal / Q000187:drug effects; D015818:Eye Infections, Bacterial / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control*; D019084:Fluorescent Antibody Technique, Indirect; D020287:In Situ Nick-End Labeling; D007634:Keratitis / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008074:Lipoproteins / Q000494:pharmacology; D051218:Lymphocyte Antigen 96 / Q000037:antagonists & inhibitors; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D009504:Neutrophils / Q000187:drug effects; D011552:Pseudomonas Infections / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control*; D011550:Pseudomonas aeruginosa / Q000502:physiology; D013403:Sugar Phosphates / Q000627:therapeutic use*; D051193:Toll-Like Receptors / Q000037:antagonists & inhibitors*
D054360:Chemokine CXCL1; C475895:Cxcl1 protein, mouse; D004187:Disaccharides; D008070:Lipopolysaccharides; D008074:Lipoproteins; C411728:Ly96 protein, mouse; D051218:Lymphocyte Antigen 96; D013403:Sugar Phosphates; D051193:Toll-Like Receptors; C512420:eritoran; C069172:2,3-bis(palmitoyloxy)-2-propyl-1-palmitoylcysteine; D003545:Cysteine